JPH0222690B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a dust removal device having a wall made of a hollow, cylindrical, air-permeable porous solid.

[Prior Art] Excessive dust removal devices made of cloth have been widely used in the past, but in the case of such dust removal devices,
Because the cloth has poor heat resistance, the temperature of the dust-containing gas is 250℃.
If it exceeds ℃, it can no longer be used.

Therefore, the present applicant has proposed a dust removal device that can be used for high-temperature dust-containing gases and is made of a porous porous ceramic material (see Japanese Patent Laid-Open No. 59-225721). In this dust removal device,
Dust-containing gas is supplied from above into an upright cylinder made of a permeable porous solid, and the clean gas flows out from the inside of the cylinder to the outside, while some of the dust that was blocked from passing by the cylinder is Deposits on the inner wall of the cylinder,
Most of the dust falls inside the cylinder and is collected in a dust hopper installed at the bottom of the cylinder.

By the way, in such an excessive dust removal device, when dust removal operations are performed continuously, the material gradually becomes clogged, the differential pressure required increases, and the overspeed decreases. For this reason, a so-called backwashing operation is required to remove clogging dust by flowing backwashing gas from the clean gas side to the dust-containing gas side every time the dust removal operation is performed for a predetermined period of time.

In dust removal equipment that uses cloth, a high-pressure gas jet nozzle is installed in the clean gas outlet piping during dust removal operation, with its opening facing the cloth side, and high-speed gas is jetted from there during backwash operation. The method is well known. According to this method, since the cloth is generally flexible, when this high-speed gas is ejected toward the cloth, the cloth flaps and vibrates.
The dust that had accumulated on the inside of the cloth is brushed off.
In addition, the cloth is generally not very thick, and the velocity energy of the high-velocity gas is not significantly attenuated when passing through the cloth, so that the dust is also blown away by the velocity energy of the high-velocity gas.

[Problems to be Solved by the Invention] However, the backwashing method used for cloth dust removal cannot be applied to a dust removal device using an air permeable porous solid (hereinafter referred to as a solid filter). That is, even when a solid filter is exposed to a high-speed gas flow, it does not flap at all, and dust is not blown off by vibration. Additionally, solid filters are generally thicker than cloth, so even if high-velocity gas hits them, their velocity energy is greatly attenuated while the gas passes from the outside to the inside of the tube, causing dust to accumulate. By the time it reaches the inner side, the speed will be much lower than its original speed.
It cannot perform sufficient backwashing function.

Therefore, it is an object of the present invention to solve such problems that cannot be solved by the conventional techniques and to provide a fixed filter type dust removal device having a truly useful backwashing function.

[Means for Solving the Problems and Their Effects] That is, the present invention supplies a dust-containing gas to the inner side of the wall made of a hollow cylindrical porous solid having air permeability, and cleans the air from the outside of the wall. In a dust removal device that extracts gas, a clean gas outlet duct is provided on a side wall of a can surrounding a clean gas chamber, an air outlet is provided inside the outlet duct, and the wall is provided between the wall and the air outlet. This dust removal device is characterized by being provided with a diff user whose diameter increases toward the side.

Therefore, according to the present invention, an airflow outlet is provided in the clean gas outlet duct, from which the airflow for backwashing is blown out. Since a diff user is provided between the wall and the air outlet, the diameter of which expands toward the wall, the blown air flows through the diff user toward the wall, and the Bernoulli's Based on the theorem, part or most of the velocity energy is efficiently converted into pressure energy, resulting in an increased pressure at the diffuser outlet, and therefore around the wall. For this reason, the clean gas side exhibits a sufficiently higher differential pressure than the dust-containing gas side across the wall, and based on this pressure difference, the airflow passes through the wall, causing clogging of the wall. It can wash out the dust that was left behind and perform the intended backwashing function.

Furthermore, according to the present invention, the increased pressure is achieved not only on the part of the wall directly facing the diffuser outlet but also on the entire wall on the clean gas side. Therefore, in a cloth-based excessive dust removal device, the backwashing function works only on the cloth in the area that is directly exposed to the high-speed gas; in other words, it does not work sufficiently on the cloth in other areas, resulting in a large number of high-pressure gas jets. Whereas it was necessary to provide a nozzle, in the present invention, a single air outlet may be used, and the position where the air outlet or diffuser is provided is not limited to a position directly facing the wall.

In the present invention, it is preferable to provide an airflow direct hit prevention body between the reduced diameter end of the diffuser and the wall. Because fixed filters are porous, they often have low mechanical strength and may be damaged by the velocity energy of the airflow from the airflow outlet. This can be prevented by Furthermore, by appropriately designing the airflow blow protector, the conversion of the velocity energy of the airflow into pressure energy is facilitated.

Although the fixed filter may be made of sintered metal, it is preferably made of ceramic because of its excellent heat resistance and corrosion resistance. Furthermore, when removing dust from high-temperature dust-containing gas by taking advantage of its heat resistance, it is not uncommon for there to be sudden temperature changes at the start and stop of operation, or temperature changes in the dust-containing gas itself. Particularly preferred is one made of ceramics. Specifically, preferred examples include those made of ceramics such as cordierite, β-spodium, zirconia, and aluminum titanate.

The wall is a hollow cylindrical tube, preferably a hollow cylindrical tube, and a dust-containing gas is supplied to the inner space. As a result, the space on the clean gas side is connected and surrounds the outside of the wall, and even if one or several diffusers are localized at a specific position in the clean gas side space, the space on the clean gas side is connected. The pressure increase effect can be spread throughout the area. Further, by forming the hollow cylindrical shape, the risk of the wall being damaged due to the pressure difference on both sides of the wall is minimized. Also, the wall may be arranged horizontally or in an inclined direction, but
Preferably, they are arranged vertically. This results in
It is possible to prevent the separated dust from falling one after another and reducing the dust removal efficiency.

The air flow outlet is provided in a clean gas outlet duct provided on the side wall of the can surrounding the clean gas chamber. Thereby, the clean gas deriving duct from the can body to the airflow outlet can also be used as a backwash gas delivery duct, and the number of openings provided in the can body can be reduced.

When providing the air flow outlet in the clean gas outlet duct, a double pipe type and a branch pipe type can be preferably proposed.

The double pipe type is a type in which a smaller diameter air outlet is installed almost coaxially inside the clean gas outlet duct.
By blowing out airflow from here, especially high-speed airflow such as the pulse jet method, clean gas existing in the surrounding area is also taken in incidentally due to the ejector effect, and the amount of gas is much larger than that blown out from the airflow outlet. This means that the gas can be used as backwash gas.

The branch pipe type is one in which a branch pipe is provided that opens into the wall of the clean gas derivation duct, and valves are preferably provided in the clean gas derivation duct downstream of this opening and in the branch pipe, respectively.According to this, the double pipe type Even if the speed is not as high as in the case, by blowing out the airflow at a certain high speed, the required amount of backwash gas can be obtained reliably and easily.

The diameter of the diff user must be expanded toward the wall. If the diameter is reduced toward the wall side, no pressure increase effect will be produced. Note that "towards the wall" means "toward the downstream direction of the backwash gas flow path," and does not necessarily mean a geometric method.

The diffuser can be installed at an appropriate position between the can side wall and the air outlet (this is also used as a flow path for backwash gas, and is not necessarily in a geometric sense); It is preferable to provide the diameter-enlarged end so that it is located approximately at the end, since this also saves space for the entire device.

The airflow direct hit prevention body can be provided at an appropriate position between the reduced diameter end of the diffuser and the wall, and preferably at a position where the flow velocity of the backwash gas is the highest in the flow velocity distribution when viewed in the radial direction. Located in the center of the road. Also, if you look at it in the flow direction,
It is preferable to provide it near the enlarged diameter end of the diff user.

A detailed description will be given below with reference to the drawings.

[Configuration of the first embodiment] In FIG. 1, a plurality of hollow cylindrical tubes 11 are connected to a cylindrical can body 12 at appropriate intervals.
is housed in. The tube 11 is made of a porous, breathable solid made of cordierite ceramics.

A header 14 equipped with a dust-containing gas inlet 13 and a hopper 16 equipped with a dust extraction valve 15 are connected to the can body 1.
It is attached above and below 2. A plurality of tube sheets 17 (four in FIG. 1) are provided inside the can body 12 to hold the tube 11. The tube sheets 17 are kept airtight with the cylinder 11 and the can body 12, respectively, and clean gas chambers 18 are formed between adjacent tube sheets 17, respectively. The upper and lower ends of the cylinder 11 are open to a header 14 and a hopper 16, respectively. It is sufficient that there are at least two tube sheets 17, and the intermediate tube sheet has clean gas chambers 18 above and below it.
It may also be something that allows communication between the two.

A diffuser 20 is provided in the can 12 corresponding to each clean gas chamber 18 so that the inner periphery of the can 12 has an enlarged diameter end. In addition, an airflow direct hit prevention body 22 is provided at the center of the enlarged diameter end via a support 21.
is provided.

A duct 25 is connected to the reduced diameter end of the differential user 20, and the plurality of ducts 25 are collected and connected to the blower 2.
6. Further, the diameter of the duct 25 is reduced at the connection portion with the reduced diameter end of the differential user 20 to form a throat portion 27 .

The piping from the baby compressor 28 is the solenoid valve 3.
5 into the duct 25 and opens toward the cylinder 11 at the shaft portion of the duct 25 at a position slightly closer to the blower 26 than the throat portion 27 to form an airflow outlet 29. Note that instead of the baby compressor 28, other high-speed airflow generating means,
For example, a compressed air cylinder, a high pressure nitrogen cylinder, etc. may be used.

[Operation of the first embodiment] This dust removal device operates as follows.

First, during dust removal operation, high-temperature dust-containing gas is introduced from the dust-containing gas inlet 13 and is distributed to each cylinder.
It flows down the inside of 1. As it flows down, the dust-containing gas is separated by the cylinder 11, and some of the dust flows into the cylinder 1.
Most of the dust accumulates on the inner wall of the hopper 16 and falls downward and accumulates in the hopper 16. The high temperature clean gas passes through the wall of the cylinder 11, enters the clean gas chamber 18, passes through the diffuser 20 and the duct 25, and is led out from the blower 26. During this time, the cylinder 11 gradually becomes clogged with dust, and the excessive resistance increases. Therefore, a backwashing operation is performed after a predetermined dust removal operation.

During the backwashing operation, the electromagnetic valve 35 is opened for a short period of time, and the high-pressure gas generated by the baby compressor 28 is ejected from the airflow outlet 29 as a gas at a speed of about the speed of sound, for example. Due to the ejector effect of the throat part 27, the backwash gas which takes in the clean gas existing in the surrounding area and whose flow rate is several times the amount of air blown out from the airflow outlet 29 is discharged from the reduced diameter end of the diff user 20 at a considerable speed. Flows toward the expanded diameter end. During this time, much of the velocity energy of the backwash gas is converted into pressure energy, increasing the pressure in the clean gas chamber 18. In addition, since the clean gas chamber 18 surrounds the cylinder 11,
Even if the diffuser 20 is provided only at a specific position of the can body 12, the entire outer circumference of the cylinder 11 is pressurized. Thus, the clean gas chamber 18
becomes higher pressure from the dust-containing gas side inside the cylinder 11,
The backwashing gas passes smoothly from the outside to the inside of the wall, thereby washing out the dust that was causing clogging, reducing the gas passage resistance of the cylinder 11, and regenerating the cylinder 11.

Note that the airflow direct hit prevention body 22 may be omitted in some cases, but if it is present, the differential user 2
It is possible to prevent the high-speed backwash gas flowing through the shaft portion of the cylinder 11 from directly hitting the cylinder 11 and damaging it, and it also contributes to improving the functionality of the differential user 20. moreover,
High-speed gas at about room temperature from the airflow outlet 29,
In many cases, the mixing with the high-temperature clean gas taken in by the ejector effect is not sufficient, and in that case, the backwash gas, which has a considerable temperature difference between the shaft and the peripheral part, remains in the cylinder at the expanded diameter end of the diff user 20. 11 and may be damaged due to thermal stress. However, if the air flow direct hit prevention body 22 is provided, mixing of backwash gas is also promoted, and such troubles can be prevented. Airflow direct hit prevention body 22
For example, a disk body 23 having a Mt. Fuji-shaped protrusion on one side as shown in FIGS. It is provided via a suitable support 21 toward the diameter-reduced end side. Instead of the disk body 23, a cross plate body 24 as shown in FIGS. 5 and 6 may be used.

Note that the dust removal operation and the backwashing operation are performed intermittently on the same part of the cylinder 11, but as shown in FIG. If so, it is also possible to backwash the entire dust removal device without interrupting the dust removal operation.

That is, in FIG.
8, and then only the lower baby compressor 28 is activated without activating the upper and middle baby compressors 28, the dust flows through the throat portion 27 to the right in FIG. 1. The leftward flow velocity of the gas ejected from the airflow outlet 29 is greater than the flow velocity of the clean gas, so that the clean gas is directed toward the tube 11 with its flow direction reversed here. Therefore, a backwash operation is performed in the cylinder 11 in the part belonging to the lower clean gas chamber 18, and the backwash gas enters the inside of the cylinder 11 from the downstream clean gas chamber 18 to regenerate the cylinder 11 in this part. At the same time, the incoming gas passes through the upper or middle cylinder 11 and exits to the upper or middle clean gas chamber. This kind of operation is carried out sequentially for the middle and upper parts of cylinder 1.
By repeating the same procedure for 1, the backwashing operation is sequentially performed for the dust removal apparatus as a whole without interrupting the dust removal operation.

[Configuration and operation of second embodiment] In another embodiment shown in FIG. 2, a branch pipe system is adopted. Incidentally, the same parts as in the case of FIG. 1 are given the same numbers and the explanation is omitted. The duct 36 has one end connected to the can body 12, and the other end is connected to the enlarged diameter end of the diffuser 20, and the backwash gas duct 31 is connected to the reduced diameter end of the diffuser 20. A clean gas duct 30 branches off at the expanded diameter end of the diffuser 20. The clean gas ducts 30 pass through a clean gas valve 32 provided midway, and then are collected and connected to the blower 26. The backwash gas duct 31 also has a backwash gas valve 3 installed in the middle.
3, they are assembled and connected to the push blower 34. Therefore, the backwash gas duct 31 functions as an airflow outlet.

In the dust removal apparatus shown in FIG. 2, during the dust removal operation, each backwash gas valve 33 is closed, the forced blower 34 is stopped, the clean gas valve 32 is opened, and the blower 26 is operated. During backwash operation, open the backwash gas valve 33,
The forced blower 34 is operated, and each clean gas valve 33 is
, and stop the blower 26. The backwashing gas that has entered the cylinder 11 from the clean gas chamber 18 opens the dust removal valve 15, for example, and is led out from there.

A preferred method of operating the dust removal apparatus of FIG. 2 is to perform the backwash operation without interrupting the dust removal operation. That is, to illustrate the case of backwashing the lower part of the cylinder 11, in the upper and middle stages, the backwash gas valve 33 is closed, the clean gas valve 32 is opened, and the blower 26 is operated. In the lower stage, the backwash gas valve 33 is opened, the clean gas valve 32 is closed, and the forced blower 34 is operated. As a result, the high-speed backwash gas from the forced blower 34 is decelerated and pressurized by the lower diff user 20 and enters the lower clean gas chamber 18, backwashes the lower part of the cylinder 11, and then backwashes the upper part of the cylinder 11. Alternatively, it passes through the wall of the middle section, enters the upper or middle clean gas chamber 18, and is discharged through the clean gas duct 30. In this way, the dust removal operation is continued in the upper and middle stages, while the backwashing operation is performed in the lower stage, and by performing this operation on the upper and middle stages as well, the dust removal operation as a whole is not stopped.
Backwash operation can be performed at each stage.

[Effects of the Invention] As described above, in the dust removal device of the present invention, the airflow outlet is provided in the clean gas deriving duct from the clean gas chamber, and the diffuser is provided between the airflow outlet and the wall. Therefore, the velocity energy of the backwashing gas is converted into pressure energy and the pressure is increased, making it possible to efficiently backwash the wall made of the fixed filter.

In addition, in the dust removal device of the present invention, the clean gas outlet duct is also used as the introduction duct for the backwash airflow, so the number of pipes installed in the clean gas chamber can be reduced, and at the same time, the hollow cylinders in the same clean gas chamber can be connected simultaneously. This has the effect of ensuring that backwashing can be regenerated.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a dust removal device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a dust removal device according to another embodiment of the present invention. FIG. 3 and FIG. 4 are a side view and a front view, respectively, of a disc body which is an example of an air flow direct hit prevention body employed in the dust removal device of the present invention. FIGS. 5 and 6 are a side view and a front view, respectively, of a cross plate body which is another example of the air flow direct hit prevention body.

Claims (1)

[Scope of Claims] 1. A dust removal device that supplies dust-containing gas to the inside of a wall made of a porous solid in the shape of a hollow cylinder having air permeability, and extracts clean gas from the outside of the wall, including a clean gas chamber. A clean gas outlet duct is provided on the side wall of the surrounding can body, the outlet duct is configured to also be used as an introduction duct for backwash airflow, an airflow outlet is provided inside the outlet duct, and the wall and the airflow A dust removal device characterized in that a diffuser whose diameter increases toward the wall is provided between the air outlet and the air outlet. 2. The dust removal device according to claim 1, wherein the enlarged diameter end of the diff user is located approximately on the inner wall of the can. 3. The dust removal device according to claim 1 or 2, wherein an airflow direct hit prevention body is provided between the diameter-reduced end of the diff user and the wall. 4. The dust removal device according to claim 1, 2, or 3, wherein the airflow outlet is provided inside the outlet duct substantially coaxially with the outlet duct.